A slide caliper such as a vernier caliper, a dial caliper, and a digital caliper, etc., has been known as a fine measurement device for accurately measuring target objects to be measured, such as industrial products and the like. Recently, a slide caliper including a thumb roller has come into wide use so as to improve measurement accuracy by finely and slightly moving a slider part provided with jaws of the slide caliper. In measurement by using the slide caliper including the thumb roller, measuring surfaces of the jaws are moved to closely approach the target object to a certain extent, and then a user operates the thumb roller by using a finger (thumb) to finely and slightly move the measuring surfaces of the jaws in a direction of the target object, thereby achieving more accurate measurement than a conventional slide caliper (a slide caliper that is not provided with a thumb roller). Meanwhile, since force (pressing force or measuring force) that presses the target object by using the thumb roller varies depending on each user, a variation with respect to a measured value occurs due to variation of the pressing force. Further, the excessive pressing force may be exerted on the target object, thereby causing damage of the target object.
Meanwhile, in consideration of the above, as disclosed in JP-A-H06-185905, proposed herein is a technology in which the excessive measuring force can be suppressed from being exerted on the target object by using a double structure including an outer roller and an inner roller (a constant-pressure means in which the outer roller idles against the inner roller) by which the measuring force is limited to be lower than predetermined measuring force. Further, as disclosed in JP-A-2015-165233, proposed herein is a technology in which a rotary-type actuation member to be operated by a user, a rotary-type bearing member, and a flexible connection member are provided. The rotary-type actuation member and the rotary-type bearing member are able to be elastically connected to each other (the flexible connection member flexibly connect the rotary-type actuation member and the rotary-type bearing member each other), such that it is advantageously possible not only to provide a thumb roller having flexibility properties, but also to reduce variation of the measuring force that is exerted on the slide caliper by the user in comparison with a thumb roller of the background art.